Abstract:

With the rising of smart substations, electronic transformers have been widely used in relay protections, but their defects are gradually exposed. A complex developing fault caused by abnormal electronic transformer was introduced, and the process and reasons for this failure were analyzed. By analyzing the abnormal sampling visit (SV) criterion and solutions for different protections on site, the operation of protection devices after the fault was detailed and discussed.It is believed that the reliability of the current electronic transformer needs to be further improved. On this basis, an optimization scheme for phase selection logic in the line protection is proposed and be proved to be feasible by a simulation test. The scheme can be applied in complex developing faults to improve the reliability of smart substations

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